The traditional monopolies of electrical utility companies have been relaxed in the past few years in the European Union and in the United States. There has developed as a result a growing market in wholesale for electric energy. Utility companies, independent power producers, and power marketers as well as brokers are some of the participants in the volatile electricity supply market. It is known, for example, that variables such as the time of day and date, weather, temperature and oil prices play a role in the pricing of electricity in a given region. Furthermore, the pricing of the electricity is dependant on the operational status of electric generation and use facilities in that region as well as the transmission capacity of an electric power transmission network. The participants in the electric power markets require access to real-time information as well as historical data on the operational status of the electric generation and use facilities as well as the electric power transmission lines in the region. This information allows the development of trading strategies in electrical power and responses to power system events (such as disruptions in the power supply due to failures of transformers).
The relaxation of the monopoly status of traditional electric utilities has resulted in increased competition for customers among suppliers of electrical energy. Information relating to the use of electrical energy by the potential customers would be extremely useful to those involved in the bidding for electrical supply contracts. It would also be further advantageous to determine information on the supply and the demand of the electrical energy over time without having to directly connect to the electrical power transmission lines.
Methods and systems for the measurement for the electrical power transmission are known from several prior art documents. For example U.S. Pat. No. 6,714,000 (Staats, assigned to Genscape, Inc.) teaches a method for the remote monitoring of the magnitude and the direction of net electrical power and count flow to or from a facility reduced monitored over a prolonged period of time. The method described in the '000 patent application” includes the detection and the measurement of the magnetic field emanating from the monitored electrical power transmission lines and detecting a signal which is synchronized to the power system frequency emanating from the power lines. The method further includes valuation, storing and transmission of the data on the electromagnetic field that emanates from the electrical power transmission line.
A further patent application, international patent application No. WO2006/112839 (Genscape Intangible Holding, Inc.) also teaches a method and a system for the substantially real-time monitoring of the operational dynamics of power plants and other components in an AC power grid. The monitoring is done by using information collected from a network of power grid frequency detection and reporting devices. The invention allows for the real-time detection and reporting of certain power grid events, such as a power plant trips or failures.
International patent application No. WO2007/030121 (Genscape Intangible Holding, Inc.) teaches a system for monitoring the power flow along an electric power transmission line which includes a plurality of magnetic field monitors placed at selected positions. The system further includes a central processing facility for the communication of the power flow to an end user.
European Patent No. EP1 297 347 (Genscape Intangible Holding, Inc.) discloses an apparatus for remotely measuring and monitoring an electric power transmission line. The apparatus comprises a first sensor which is responsive to a first component of a magnetic flex density associated with the electric power transmission lines and which outputs a volt proportional to the magnetic flex density generated by current flowing through set electrical power transmission line. The apparatus further includes a second sensor which outputs a voltage proportional to a net electrical potential associated with the electrical power transmission line. The values for the voltage and the current flowing through the electrical power transmission line are passed to a central processing facility which combines the phase of the measured electrical potential with the phase of the measured magnetic flex density in order to determine the phase of the electrical potential relative to the magnetic flux density and that by determining from the face of the electrical potential relative to the magnetic flux density. The phase angle of the current flowing through the electrical power transmission line with respect to the voltage of the transmission line is also determined. A power factor on the electric power transmission line and the magnitude and the direction of the power flowing through the electrical power transmission line is thereby calculated. It should be noted that the voltage sensor and the magnetic flux sensor are substantionally co-located, as can be seen from FIG. 1 of the patent.
Other companies also measure power flowing along transmission lines. For example, the Norwegian company powermonitor.org supplies information about the German power plants. Their product is described in the article “Slik drives strøm-spionasje”,Økonomisk Rapport April 2006, 40-41. Another Norwegian company, Energieinfo AS, Stavern, has filed a Norwegian patent application entitled “Fremgangsmåte og apparat for overvåkning av produksjon og overføring av elektrisk kraft” (Application No. NO 2007 2653). The contents of this application are, however, not yet public.